How long does it take electrons to get from a car battery to the starting motor? Assume the current is 300 A and the electrons travel through a copper wire with cross-sectional area 0.250 cm2 and length 0.900 m. The number of charge carriers per unit volume is 8.49 × 1028 m-3.

16.98 minutes

Explanation:

We are given that

Current,I=300 A

Area, A=0.250 square cm=

Length of wire,d=0.9 m

Number of charge carriers per unit volume=

We know that

Using the formula

work: w = fd (given)

work done by chet   =50*1 = 50 j

work done by mika =40*2 = 80 j

work done by sara =30*1.5 = 45 j

work done by bill =60*0.5 = 30 j

students in order from the greatest amount of work done to the least is mika> chet> sara> bill

hence option (b) is correct.